1. Field
Embodiments relate to an induction heating cooker able to heat a container regardless of the position of the container on a cooking plate.
2. Description of the Related Art
In general, an induction heating cooker supplies high-frequency current to a heating coil so as to generate a strong high-frequency magnetic field in the heating coil and generates eddy current in a cooking container (hereinafter, simply referred to as a container) magnetically coupled to the heating coil through the high-frequency magnetic field such that the container is heated by Joule's heat so as to cook food.
In such an induction heating cooker, a plurality of heating coils to provide a heating source is fixedly mounted inside a main body forming appearance. In addition, a cooking plate on which a container is placed is provided on an upper side of the main body. On this cooking plate, a container mark is formed at a position corresponding to the heating coil so as to enable a user to accurately place a container.
However, in order to cook food (heat the container) using such an induction heating cooker, the user needs to accurately place the container at a specific position of the cooking plate. That is, if a user does not place a container at an accurate position, food is not evenly heated.
Accordingly, a new induction heating cooker to cook food, regardless of the position of the container on a cooking plate, by arranging a large number of heating coils below the entire surface of the cooking plate has been developed.
If food is cooked using the newly developed induction heating cooker, it is necessary to perform an operation (container position detection operation) to detect a position where a container is placed on a cooking plate after a user places the container on the cooking plate and before a cooking operation starts.
In order to detect the position of the container on the cooking plate, a method of enabling high-frequency current to flow through the plurality of heating coils arranged below the cooking plate, measuring the value of current flowing through the heating coils, and detecting whether or not the container is placed on the heating coils using the measured current is used.
In the newly developed induction heating cooker, since the small-sized heating coils are densely arranged below the entire surface of the cooking plate, a distance between the heating coils is very small. In such an induction heating cooker, if high-frequency current is simultaneously supplied to all the heating coils in order to detect the position of the container, magnetic field interference occurs between adjacent heating coils and thus a container position detection error may occur. That is, when current flowing through any one heating coil (first heating coil) is measured to detect whether or not a container is placed on the heating coil (first heating coil), noise occurs by magnetic field interference with adjacent heating coils (second and third heating coils). Accordingly, it may be erroneously determined that the container is placed on a heating coil although the container is not actually placed on the heating coil. At this time, as a distance between heating coils is decreased, magnetic field interference with the adjacent heating coils is increased.
If a cooking operation is performed in a state in which a container position detection error has occurred, a heating coil on which the container is not actually placed is also driven. Thus, unnecessary power is consumed and an inverter (circuit element) included in the induction heating cooker may be damaged.